Manufacture of integrated circuit (IC) packages may involve, among other processes, the installation of an Integrated Heat Spreader (IHS) onto the IC package. During an IHS installation process, a heatspreader lid is adhered to a substrate while the package is mounted in a process carrier. The lid is affixed to the substrate using an epoxy adhesive and a layer of thermal grease is applied between the die and the lid. Thermal conductivity between the heatspreader lid and the die has been found to be dependent on the application force of the lid. A bridge clip is used to secure the package in the process carrier and apply force to the heatspreader lid during the application and cure stages of the lid. That is, once the heatspreader lid is in place, the bridge clip is fastened to the process carrier to hold the package in place in the process carrier and maintain an appropriate force on the heatspreader lid while the epoxy adhesive is being cured.
To ensure proper heat transfer from the substrate to the IHS, the force asserted by the bridge clip onto the IHS lid should be maintained within an appropriate range. Stiffness of the bridge clip is an important factor in any deviations in the resulting force from the bridge clip. However, excessive stiffness may result in a clip that degrades in performance after repeated insertion into the process carrier due to the clip being stressed when it is compressed to be latched to the process carrier.
Therefore, bridge clip designs address opposing goals. First, the bridge component links two latching points on the process carrier and applies a securing force on the center of the HIS lid. Therefore, the clip should have sufficient thickness and rigidity to allow it to maintain a steady force of 3-8 kg on the IC package. However, the clip should also be flexible enough to be easily and quickly manipulated by the handling equipment. Additionally, the clip should have sufficient spring characteristics to maintain its shape and dimensions through repeated manipulations by the handling equipment. These spring characteristics improve the clip's usable life span.
Previous bridge clip designs have focused on maintaining adequate stiffness to ensure that the proper amount of force is applied to the IHS lid. As a result, flexibility of the previous bridge clip designs is relatively low resulting in poor spring characteristics and a short usable life span. No previous bridge clip design has adequately addressed the contrary goals of maintaining adequate stiffness to ensure that the proper amount of force is applied to the IHS lid while remaining flexible enough to provide a long usable life span.